Question

the boom of the wall crane 4m long is held at right angles to the wall by a wire that is attached to the wall above the foot of the boom. If the load lifted is 45 000 N, find the tension in the wire and the compression force in the boom. Neglect the weight of the boom

Answer 1

The compression force in the boom:

$$R=\frac{4}{3}W\\R=\frac{4}{3}45 000=60000\ N$$

The tension in the wire:

$$T=\frac{\sqrt{3^2+4^2}}{3}W\\T=\frac{\sqrt{3^2+4^2}}{3}45 000=75000\ N$$